It would cost between $3000 - $4000 for 13 m2 depending what timber and size you want to use.
If you are interested I can quote the deck for you. I'm a qualified carpenter. Just PM if your interested or have any questions.
Regarding concreting, you can use a bearer and joist system if you are not concreting or, if using concrete, the use of timber battens on top of the concrete. Really up to you on what you want to do.
Adam
Hi Adam. Are you local?